• Journal of Genetic Medicine
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• 제12권2호
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• pp.100-108
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• 2015

Purpose: Conventional methods for the prenatal detection of fetal RhD status involve invasive procedures such as fetal blood sampling and amniocentesis. The identification of cell-free fetal DNA (cffDNA) in maternal plasma creates the possibility of determining fetal RhD status by analyzing maternal plasma DNA. However, some technical problems still exist, especially the lack of a positive control marker for the presence of fetal DNA. Therefore, we assessed the feasibility and accuracy of fetal RHD genotyping incorporating the RASSF1A epigenetic fetal DNA marker from cffDNA in the maternal plasma of RhD-negative pregnant women in Korea. Materials and Methods: We analyzed maternal plasma from 41 pregnant women identified as RhD-negative by serological testing. Multiplex real-time PCR was performed by amplifying RHD exons 5 and 7 and the SRY gene, with RASSF1A being used as a gender-independent fetal epigenetic marker. The results were compared with those obtained by postnatal serological analysis of cord blood and gender identification. Results: Among the 41 fetuses, 37 were RhD-positive and 4 were RhD-negative according to the serological analysis of cord blood. There was 100% concordance between fetal RHD genotyping and serological cord blood results. Detection of the RASSF1A gene verified the presence of cffDNA, and the fetal SRY status was correctly detected in all 41 cases. Conclusion: Noninvasive fetal RHD genotyping with cffDNA incorporating RASSF1A is a feasible, reliable, and accurate method of determining fetal RhD status. It is an alternative to amniocentesis for the management of RhD-negative women and reduces the need for unnecessary RhIG prophylaxis.

• 대한인간공학회지
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• 제29권1호
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• pp.121-128
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• 2010

The purpose of this study is to confirm the impact of noise on subject accomplishment as well as physical/mental load, and evaluates the effects of noise-masking and earplug. 15 college students participate in the test, and the comparison is performed by executing four projects according to conditional categories of noise environments; control condition, noise condition, earplug condition, and noise-masking condition. Noise in the field site of the H manufacturer was used as the noise source, the general job aptitude test which consist of linguistic ability, math ability, perception ability, reasoning ability was used as the task of this project. To estimate physical/mental load evaluation, we used the heart rate R-R interval, Criteria flicker fusion frequency(CFF) and measured NASA-TLX workload for subjective evaluation. As the research outcome, it is shown that there is a meaningful difference for the project task score, dropping rate of CFF, the heart rate, and NASA-TLX subjective evaluation score according to conditions of noise environment. Therefore, the impact of noise on capability of subject accomplishment as well as physical/mental load was confirmed along with the effects of using earplug and noise-masking.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1995년도 추계학술대회논문집; 한국종합전시장, 24 Nov. 1995
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• pp.136-141
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• 1995

Room Air Conditioner(이하 RAC) 실내기는 열교환기, Cross Flow Fan(이하 CFF), 곡률, Stabilizer(이하 STB) 등 여러 설계인자가 소음, 풍량 및 압력 등에 상호 복합적으로 연성(Coupled)되어 있어 각 인자가 성능에 미치는 영향을 정량적으로 밝혀 내기가 쉽지 않다. 따라서 RAC 실내기의 고성능 및 저소음화를 실현하기 위해서는 실내기를 구성하는 각 인자간의 상호 관련성 및 각 인자가 소음.성능 등에 미치는 영향을 체계적으로 분석하는 것이 필수적이다. 본 연구에서는 설계인자중 소음 및 풍량에 민감한 영향을 주는 STB 위치 및 형상 등에 관하여 자세히 다루고자 한다. STB위치의 적절한 범위를 설정하기 위해 Laser Doppler Velicitimeter(이하 LDV)를 이용하여 곡률별 실내기 내부의 유속분포 및 속도 벡터를 측정하였고, CFF내부 Vortex의 정확한 위치를 찾아냈다. 또한 실내기 저소음화를 위한 소음원 규명 측면에서 실내기 내부의 난류도와 관련하여 속도 Fluctuation을 정의하고, 실험을 통해 구하였다.

• Safety and Health at Work
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• 제13권2호
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• pp.148-154
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• 2022

Background: Bus driving is a mentally demanding activity that requires prolonged attention to ensure safety. The aim of the study was to assess mental fatigue caused by driving a public bus and to find a profile of workers at higher risk. Methods: We evaluated changes of critical flicker fusion (CFF) (index of central arousal) and heart rate variability (HRV) (index of autonomic balance) in a 6-hour driving shift on a real route, in 31 professional bus drivers, and we tested the influence of personal factors such as sleep quality, BMI, and age. Paired t-test was used to test differences of CFF and HRV between both initial and final phase of driving, while multiple linear regression tested the influence of personal variables on the indexes of mental fatigue. Results: Results showed that CFF significantly decreased after 6 hours of bus driving (41.91 Hz, sd 3.31 vs. 41.15 Hz, sd 3.15; p = 0.041), and heart rate significantly decreased in the final phase of driving, with respect to the initial phase (85 vs. 78 bpm, p = 0.027). Increasing age (beta = -0.729, p = 0.022), risk of obstructive sleep apnea syndrome (beta = -0.530, p = 0.04), and diurnal sleepiness (beta = -0.406, p = 0.017) showed a significant effect on influencing mental fatigue. Conclusion: Elderly drivers at higher risk of sleep disorders are more prone to mental fatigue, when exposed to driving activity. Monitoring indexes of central arousal and autonomic balance, coupled with the use of structured questionnaires can represent a useful strategy to detect profile of workers at higher risk of mental fatigue in such duty.

• Journal of Microbiology and Biotechnology
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• 제33권5호
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• pp.607-620
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• 2023

The biocontrol approach using beneficial microorganisms to control crop diseases is becoming an essential alternative to chemical fungicides. Therefore, new and efficient biocontrol agents (BCA) are needed. In this study, a rhizospheric actinomycete isolate showed unique and promising antagonistic activity against three of the most common phytopathogenic fungi, Fusarium oxysporum MH105, Rhizoctonia solani To18, and Alternaria brassicicola CBS107. Identification of the antagonistic strain, which was performed according to spore morphology and cell wall chemotype, suggested that it belongs to the Nocardiopsaceae. Furthermore, cultural, physiological, and biochemical characteristics, together with phylogenetic analysis of the 16S rRNA gene (OP869859.1), indicated the identity of this strain to Nocardiopsis alba. The cell-free filtrate (CFF) of the strain was evaluated for its antifungal potency, and the resultant inhibition zone diameters ranged from 17.0 ± 0.92 to 19.5 ± 0.28 mm for the tested fungal species. Additionally, the CFF was evaluated in vitro to control Fusarium wilt disease in Vicia faba using the spraying method under greenhouse conditions, and the results showed marked differences in virulence between the control and treatment plants, indicating the biocontrol efficacy of this actinomycete. A promising plant-growth promoting (PGP) ability in seed germination and seedling growth of V. faba was also recorded in vitro for the CFF, which displayed PGP traits of phosphate solubilization (48 mg/100 ml) as well as production of indole acetic acid (34 ㎍/ml) and ammonia (20 ㎍/ml). This study provided scientific validation that the new rhizobacterium Nocardiopsis alba strain BH35 could be further utilized in bioformulation and possesses biocontrol and plant growth-promoting capabilities.

• 한국수소및신에너지학회논문집
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• 제25권2호
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• pp.131-138
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• 2014

Highly conductive bipolar plate for polymer electrolyte membrane fuel cell (PEMFC) was prepared using phenol novolac-type epoxy/graphite powder (GP)/carbon fiber filament (CFF) composite, and a rubber-modified epoxy resin was introduced in order to give elasticity to the bipolar plate graphite fiber (GF) was incorporated in order to improve electrical conductivity. To find out the cure condition of the mixture of novolac-type and rubber-modified epoxies, differential scanning calorimetry (DSC) was carried out and their data were introduced to Kissinger equation. And tensile and flexural tests were carried out using universal testing machine (UTM) and the surface morphology of the fractured specimen and the interfacial bonding between epoxy matrix and CFF or GF were observed by a scanning electron microscopy (SEM).

• Advances in concrete construction
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• 제12권6호
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• pp.469-477
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• 2021

Keratin fibres are waste products of the poultry industry. Natural materials made from chicken feather fibres (CFFs) are used in concrete-reinforced composites in this study. Brittleness is a major problem of high-strength concrete (HSC) that leads to sudden failure at the ultimate capacity of concrete. Hence, this work aims to investigate effects of using CFFs on improving the brittle behaviour of HSC. Two scenarios are performed to analyse the effectiveness of using CFFs. HSC containing different ratios of CFF (0% as the control, 0.5%, 1%, 1.5%, 2%, and 3%) by volume are tested in the first scenario. Glass fibres (GF) are used to replace CFFs in the other scenario. Tests of fresh, hardened and morphological properties for concrete are performed. Results showed the enhanced brittle behaviour of HSC when using both types of fibres. The preferable ratio of both types of fibres is 1% by volume. Flexural and splitting tensile strengths increased by about 44.9 % and 42.65 % for mixes containing 0.1% GF, respectively. While they were increased by about 21.6 % and 21.16 % for mixes containing 0.1% CFF, respectively.

• 한국식품영양과학회지
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• 제38권10호
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• pp.1373-1380
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• 2009

학동기 아동은 신체 발육이 왕성하고 평생의 식습관을 형성하는 과정인 만큼 칼슘확보를 위한 다양한 시도가 필요하다. 본 연구는 우유나 유 가공품을 기피하거나 충분히 섭취하지 못하는 일부 아동들의 식생활을 보완할 수 있도록 학교급식에서 공급할 수 있는 고칼슘음식의 개발을 시도하였다. 이를 바탕으로 경기도 초등학교 영양사를 대상으로 칼슘영양 및 칼슘강화에 대한 인식과 개발된 칼슘급원음식의 수용도를 설문조사하여 분석하였다. 조사대상 영양사(총 118명)들의 90% 이상이 학교급식 식단구성에서 칼슘의 중요성은 잘 인식하고 있었다. 학교급식에서 우유공급은 79.7%의 영양사가 '매일' 또는 '일부' 한다고 응답하였다. 우유 외에 칼슘공급 음식개발의 필요성은 80%의 영양사가 인식하고 있었으나 실제 개발은 30% 수준이었다. 20종의 개발된 고칼슘 음식의 칼슘함유량이 1식당 학교급식 칼슘권장량을 초과한 음식은 3종이었으며 수용도 4점 이상(최고 5점)을 받은 음식은 2종으로 제한되었다. 참치추어강정, 무청김치치즈전, 치즈멸치볼, 무청갈비찜은 칼슘함량과 수용도 모두에서 우수하였다. 수용도는 연령에 영향을 받아 20대 영양사군에서 높았다. 칼슘강화식품에 대한 인식은 사용에 긍정적인 응답이 41.5%, 부정적 응답이 33.0%였다. 사용정도는 '사용한다'는 38.1%, '사용하지 않는다'는 응답이 48.4%에 달하였다. 칼슘강화식품에 대하여 대상자들은(70.3%) 잘 인지하고 있었으며 칼슘강화식품 사용의사에 대해서는 39.8%가 '있다', 33.1%는 '없다'고 응답하였다. 칼슘강화식품에 대하여 20대군이 30대 이상 군에 비해 칼슘강화식품에 대한 긍정적인 생각과 높은 이용의도를 보였다. 학교급식에서 우유공급을 하지 않는 군이 공급 군들에 비하여 칼슘강화식품에 대해 더 긍정적 인식을 가졌으며 칼슘강화식품 사용정도와 이용의도가 유의적이지는 않으나 높았다. 또한 칼슘공급 음식개발 필요성을 높게 인식하거나 많이 개발하는 군에서 칼슘강화식품에 대해 더 긍정적이었으나, 실제 사용 정도 및 이용의도에서는 차이가 없었다.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1998년도 춘계학술대회논문집
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• pp.161-166
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• 1998

In this study, the optimum criteria of space between the lines and the letters which could largely affect the legibility were found by the experiment and were presented as guidelines to design Korean VDT screens. Since the experiment was designed to test the human performance based on the VDT screen design, searching speed (S.S) and error rate (E) were used as the criteria of performance, and CFF value was measured to evaluate user's visual fatigue. The EOG value was also measured for the visual restriction during the experiment for the space between the lines and letters.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1994년도 춘계공동학술대회논문집; 창원대학교; 08월 09일 Apr. 1994
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• pp.112-121
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• 1994

Studies on visual fatigues were activated after VDTs were rapidly introduced into the office works in 1980s. Various measurement methods and its measures were developed from those studies. Early studies frequently used simple measures such as near point of accommodation, near point of vergence, and CFF. Current researches focus on dark focus, dark vergence, and VEP which have a good relevance to the visual fatigues. In spite of the merit they also have some limits and disagreements. This survey summarizes the measures, measurement methods and relevant researches. Finally several topics are proposed for the future researches in Korea.